采用低温液相法(LTAS)制备浆料结合水热后处理工艺,得到分散性良好、羟基缺陷少、平均粒径为50~100nm的BaZr0.2Ti0.8O3纳米粉体。采用X射线衍射、热重分析、TEM等表征手段,考查了水热温度、水热时间及初始7/(Ba)/n(Ti+Zr)对粉体颗粒形貌、粒度大小及羟基脱除情况的影响。研究表明,水热温度、水热时间及初始r/(Ba)/7/(Ti+Zr)均影响BaZr0.2Ti0.8O3晶格中羟基缺陷的脱除,但初始n(Ba)n(Ti+Zr)对粒度的影响比水热条件影响更为显著,说明可通过调整初始下料比有效控制粒度大小而羟基缺陷的脱出可通过调整水热工艺控制。该粉末烧结性能良好,在1000℃下烧结BaZr0.2Ti0.8O3得到陶瓷体介温曲线明显展宽且室温下介电常数高达8000。
Well-dispersed and low hydroxyl content BaZr0.2Ti0.8O3 nano-powder with an average grain size about 50-100 nm was prepared by a low temperature aqueous solution method combined with hydrothermal posttreatment. The effect of hydrothermal temperature and time and initial n (Ba)/n (Ti + Zr) molar ratio on grain size and shape and hydroxyl defect removal in BaZro.2Tio.803 nano-powders was investigated by means of XRD, TG and TEM. The results show that the hydrothermal temperature and time and the initial n (Ba)/n (Ti + Zr) ratio all affect the removal of hydroxyl groups from the BaZr0.2Ti0.8O3 while the initial n (Ba)/n (Ti + Zr) ratio had a greater effect on grain size than varying the hydrothermal conditions, which means we can control the grain size and hydroxyl content by adjusting the initial n (Ba)/n (Ti + Zr) ratio and hydrothermal conditions re- spectively. The resulting BaZr0.2Ti0.8O3 shows good sinterability, and even sintered at temperatures as low as 1000℃ The permittivity-temperature curve is significantly broadened and its room temperature permittivity is about 8000.